Method of forming a temporary implant and mold assembly for same

Abstract

A mold assembly and method of forming a surgical implant from bone cement. The method has the steps of connecting a plurality of mold segments to approximate the size of a patient implant. Each mold segment has an open channel. The method may further include aligning the channels of connected mold segments, positioning a centralizing holder on a reinforcement member, mixing bone cement, pouring at least some bone cement through the channels and into connected mold segments, fitting the reinforcement member into the mold segments, curing the bone cement; and removing the cured surgical implant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Still other advantages of the present invention will become apparent to those skilled in the art after reviewing the detailed description that follows made with reference to accompanying drawings in which:

FIG. 1 a is a top schematic view of a fully assembled hip implant mold according to a first preferred embodiment of the present invention;

FIG. 1 b is a right side, schematic view of the fully assembled hip mold from FIG. 1a;

FIG. 2 a is a front axial schematic view of the FIG. 1a hip mold;

FIG. 2 b is a rear axial schematic view of the FIG. 1a hip mold;

FIG. 3 a is a top schematic view of the hip head segment for the hip mold of FIG. 1a;

FIG. 3 b is a right side schematic view of the FIG. 3a hip head segment;

FIG. 3 c is a bottom schematic view of the FIG. 3a hip head segment;

FIG. 4 a is a front axial schematic view of the FIG. 3a hip head segment;

FIG. 4 b is a rear axial schematic view of the FIG. 3a hip head segment;

FIG. 5 a is a top schematic view of a connector segment for the FIG. 1a hip mold;

FIG. 5 b is bottom schematic view of the FIG. 5a connector segment;

FIG. 6 a is a top schematic view of s hip head and connector segment joined together;

FIG. 6 b is a bottom schematic view of the FIG. 6a joined hip head and connector segments;

FIG. 6 c is a left side schematic view of the FIG. 6a joined hip head and connector segments;

FIG. 7 a is a front axial schematic view of the stem segment for the FIG. 1a hip mold;

FIG. 7 b is a rear axial schematic view of the FIG. 7a stem segment;

FIG. 8 a is a top schematic view of the hip head, connector and stem segments which, when joined together, make up the exterior shell for the FIG. 1a hip mold;

FIG. 8 b is a bottom schematic view of the FIG. 8a hip head, connector and stem segments;

FIG. 8 c is a left side schematic view of the FIG. 8a hip head, connector and stem segments;

FIG. 9 a is a top schematic view of a segment joinder clip and reinforcement member holder according to one embodiment of the present invention;

FIG. 9 b is a bottom schematic view of the FIG. 9a segment joinder clip and reinforcement member holder;

FIG. 9 c is a side view of the FIG. 9a segment joinder clip and reinforcement member holder;

FIG. 10 a is a top schematic view of two segment joinder clips on a reinforcement member positioned beneath joined hip head, connector and stem segments;

FIG. 10 b is a close up, side schematic view showing the curved end to a hip mold reinforcement member with two segment joinder clips thereon;

FIG. 10 c is a front axial schematic view of the FIG. 10b hip mold central reinforcement member with two spaced apart, segment joinder clips;

FIG. 11 a is a top schematic view of a hip head segment with a reinforcement member and one segment joinder clip thereon;

FIG. 11 b is a right side schematic view of the FIG. 11a hip head segment, reinforcement member and one segment joinder clip;

FIG. 11 c is a rear axial schematic view of the FIG. 11a hip head segment, reinforcement member and one segment joinder clip;

FIG. 12 a is a top schematic view of a hip head and connector segments joined together with a reinforcement member and one segment joinder clip partially installed in same;

FIG. 12 b is a right side schematic view of the FIG. 12a joined hip head and connector segments with central reinforcement member and one segment joinder clip therein;

FIG. 13 is a top schematic view of a fully assembled, small femoral knee mold according to another preferred embodiment of this invention;

FIG. 14 a is a top view of a fully assembled, large femoral knee mold according to another preferred embodiment;

FIG. 14 b is a left side schematic view of the fully assembled, large femoral knee mold from FIG. 14a;

FIG. 14 c is a front axial schematic view of the fully assembled, large femoral knee mold from FIG. 14a;

FIG. 15 a is a front axial schematic view of a small femoral knee segment according to the invention;

FIG. 15 b is a front axial schematic view of a large femoral knee segment for comparing with smaller knee segment at FIG. 15a;

FIG. 16 a is a rear axial schematic view of a small femoral knee segment according to the invention;

FIG. 16 b is a rear axial schematic view of the large femoral knee segment for comparing with its smaller knee equivalent at FIG. 16a;

FIG. 17 a is a top, channel schematic view of a large femoral knee segment according to one embodiment of the invention;

FIG. 17 b is a bottom schematic view of the FIG. 17a large femoral knee segment;

FIG. 18 a is a top schematic view of a small femoral knee mold segment with a reinforcement member merely laid in same;

FIG. 18 b is a top schematic view of a large femoral knee mold segment with a reinforcement member laid in for generally comparing with the smaller segment at FIG. 18a;

FIG. 19 a is a top schematic view of one embodiment of reinforcement member for a small femoral knee segment according to the invention;

FIG. 19 b is a right side schematic view of the FIG. 19a femoral knee segment reinforcement member;

FIG. 190 c is a front axial schematic view of the FIG. 19a reinforcement member;

FIG. 20 a is a top schematic view showing one embodiment of femoral knee segment reinforcement member holder per this invention;

FIG. 20 b is a side schematic view of the FIG. 20a mold segment reinforcement member holder;

FIG. 21 a is a top schematic view of a fully assembled, tibial knee mold according to another preferred embodiment of the present invention;

FIG. 21 b is a right side schematic view of the tibial knee mold from FIG. 21a;

FIG. 21 c is a slightly tilted, rear axial schematic view of the tibial knee mold from FIG. 21a;

FIG. 22 a is a top schematic view of a stemmed, tibial knee segment according to the present invention;

FIG. 22 b is a right side schematic view of the stemmed, tibial knee segment from FIG. 22a;

FIG. 22 c is a bottom schematic view of the FIG. 22a stemmed, tibial knee segment;

FIG. 23 a is a top schematic view of one embodiment of reinforcement member for a stemmed, tibial knee segment according to the invention;

FIG. 23 b is a bottom schematic view of the FIG. 23a tibial knee segment reinforcement member;

FIG. 23 c is a front axial schematic view of the FIG. 23a reinforcement member;

FIG. 23 d is a rear axial schematic view of the FIG. 23a reinforcement member;

FIG. 24 a is a top schematic view of one embodiment of tibial knee segment reinforcement member holder according to the invention;

FIG. 24 b is a side schematic view of the same knee segment reinforcement member holder as in FIG. 24a;

FIG. 24 c is a slightly angled, bottom perspective schematic of the tibial knee segment reinforcement member holder from FIG. 24a;

FIG. 25 a is a top schematic view of a tibial knee segment reinforcement member with the reinforcement member holder positioned thereon;

FIG. 25 b is a side schematic view of a the reinforcement member and reinforcement member holder from FIG. 25a;

FIG. 26 is a side schematic view of the femoral and tibial knee implants made from mold similar to the ones shown in FIGS. 13 and 21 respectively; and

FIG. 27 is a top schematic view showing an assembled hip mold in vacuum drawn, packing (with insulation removed for illustrative purposes) for holding during cement filling and curing.

Claims

1. A method of forming a surgical implant for a patient made from bone cement, said method comprising: (a) connecting a plurality of mold segments to approximate a size of the implant, each segment having an open channel;(b) aligning the channels of adjacent connected mold segments;(c) positioning a mold centralizer on an appropriately sized reinforcement member;(d) mixing bone cement;(e) pouring a first quantity of bone cement through the channels of and in connected mold segments;(f) fitting the reinforcement member and mold centralizer into the connected mold segments;(g) pouring a second quantity of bone cement about the reinforcement member to substantially fill the connected mold segments;(h) curing the bone cement; and(i) removing the mold segments from about the cured cement to form the surgical implant.

2. The method of claim 1 which further comprises adding antibiotic to the bone cement during the mixing step.

3. The method of claim 1 which further comprises loading the cement in an applicator after the mixing step.

4. The method of claim 1, wherein said mold segments include a plurality of apertures through which bone cement passes for indicating substantial filling of the mold with bone cement.

5. The method of claim 1, wherein one or more mold segments are disposable.

6. The method of claim 1, wherein the mold segments are cut away from the temporary implant during the removing step.

7. The method of claim 1 which further comprises positioning connected mold segments in a holding apparatus before the first pouring step.

8. The method of claim 1, wherein the implant is used for replacing an articular joint in the patient.

9. The method of claim 1, wherein the implant is used for replacing a metaphyseal joint in the patient.

10. The method of claim 1, wherein the implant is used for replacing a diaphyseal joint in the patient.

11. The method of claim 1, wherein the implant is used for replacing one or more hip, knee, leg or ankle bones in a patient.

12. The method of claim 1, wherein the implant is used for replacing one or more shoulder, elbow, arm or wrist bones in a patient.

13. The method of claim 4 which further comprises removing excess bone cement that has passed through the mold segment apertures.

14. The method of claim 13, wherein the mold segments are made of an opaque material for visually determining when bone cement has passed through the mold segment apertures.

15. The method of claim 6, wherein an exterior of one or more mold segments is pre-scored.

16. The method of claim 10, wherein the holding apparatus comprises vacuum extraction packing and an insulated cover.

17. A method of forming an articular joint implant for a patient from bone cement and one or more antibiotics, said method comprising: (a) connecting an appropriate length of mold segments to approximate the size of an implant needed, at least some of said mold segments having a slotted channel and a plurality of apertures through which bone cement passes, the apertures are used to determine substantial filling of mold regions with bone cement;(b) aligning the slotted channels of adjacent mold segments;(c) positioning a plurality of spacers on a central reinforcement member;(d) connecting the spacers to a plurality of mold segment joinders;(e) mixing bone cement with one or more antibiotics;(f) holding connected mold segments substantially level in a holding apparatus;(g) pouring a first quantity of bone cement into the connected mold segments;(h) placing the reinforcement member into the poured bone cement in the connected mold segments to surround the reinforcement member; and(i) curing the bone cement and removing the mold segments from about the cured cement to form the implant for placing in a patient.

18. The method of claim 17, wherein the articular joint implant is selected from the group consisting of a hip, knee, leg or ankle bone.

19. The method of claim 17, wherein at least some of the mold segment exteriors are pre-scored.

20. A mold assembly suitable for making a temporary surgical implant comprises: a first mold segment selected from a first set of patient bone sizes; anda second mold segment selected from a second set of patient bone sizes, said first and second mold segments being sleeved to connect at one end, each mold segment having a slotted channel through which bone cement is poured for making the temporary surgical implant.

21. The mold assembly of claim 20 which further includes a plurality of intermediate mold segments, channeled and designed to space apart the first and second mold segments when assembled to form the temporary surgical implant.

22. The mold assembly of claim 20 which further includes a reinforcement member for fitting through the slotted channels and into both the first and second mold segments.

23. The mold assembly of claim 20 which is used to form a hip implant.

24. The mold assembly of claim 20 which is used to form a femoral and tibial knee implant.

25. The mold assembly of claim 20 having an antibiotic compound to deliver antibiotics to an infected site.